Alternating Sequence Controlled Copolymer Synthesis of α-Hydroxy Acids via Syndioselective Ring-Opening Polymerization of <i>O</i>-Carboxyanhydrides Using Zirconium/Hafnium Alkoxide Initiators
challenges until now for lack of suitable catalysts/initiators. In this work, a highly syndioselective ROP of OCAs system as the first stereoselective example in this area is reported using zirconium/hafnium alkoxides as initiators with the highest Pr value up to 0.95. Furthermore, these initiators were successfully applied in the precisely alternating sequence controlled copolymerization of PheOCA and
Bare Histidine-Serine Models: Implication and Impact of Hydrogen Bonding on Nucleophilicity
作者:Julien Leclaire、Messaoud Mazari、Yuan Zhang、Colin Bonduelle、Olivier Thillaye du Boullay、Blanca Martin-Vaca、Didier Bourissou、Innocenzo De Riggi、Rémy Fortrie、Frédéric Fotiadu、Gérard Buono
DOI:10.1002/chem.201301275
日期:2013.8.19
A new family of 2‐hydroxyalk(en/yn)ylimidazoles has been evaluated as serine–histidine bare dyad models for the ring‐opening reaction of L‐lacOCA, a cyclic O‐carboxyanhydride. These models were selected to unravel the implication of intramolecular hydrogenbonding and to substantiate its influence on the nucleophilicity of the alcohol moiety, as it is suspected to occur in enzyme active sites. Although